Approximately 8.5 billion broilers are raised and harvested by the domestic poultry industry every year. The manure by-product of the industry is mixed with absorbent materials such as pine shavings, rice hulls, or peanut hulls to create a biodegradable product commonly known as “poultry litter”. The industry generates approximately 17 million tons of poultry litter per year. The litter is high in nitrogen and phosphorous and consequently makes an excellent fertilizer, however there are problems and issues associated with the agricultural application of the litter.
The most common method of applying the litter to farmland is to simply broadcast the litter across the surface of the soil. Although this method is relatively quick and inexpensive, it is inefficient and may damage the environment. To be beneficial, the nutrients within the litter must vertically penetrate the soil to reach the root systems of the associated crops. However, heavy rains may dissolve the soluble materials within the litter and carry the nutrients away from the crops and into the area watershed, thereby contaminating local lakes and streams. Further, in areas where litter is applied repeatedly to the soil surface, the chemical nutrients within the litter may become concentrated on the soil's surface so that associated crops are damaged or otherwise adversely affected. Consequently state and federal guidelines may prohibit further surface application of litter until levels of some of the potentially damaging chemicals have decreased and normalized.
An alternative approach is to trench a field and simultaneously place the litter (or other materials) into a relatively deep trench so that a greater amount of material can be deposited without the environmental problems associated with surface applications. This approach is described and exemplified by U.S. Pat. No. 5,401,119 to Washington et al (hereinafter “Washington”). However, the dimensions of the trench described in Washington preclude this method from being employed in close proximity to the root systems of crops, which could be damaged by the deep trenching process. Further, the deep trenching process is relatively slow and a significant amount of power is required to tow the Washington placement device, particularly in applications in which multiple trenching devices are employed simultaneously.
The need exists for an apparatus capable of placing poultry litter (or any other matter) at a sufficient depth so that the nutrients associated with the matter are not easily lost to runoff. The biodegradable matter should be placed at a sufficient depth to facilitate the penetration of the soil by the fertilizing elements of the matter, but shallow enough not to disturb row crops. The current invention allows the placement of biodegradable matter in multiple trenches that are two to three inches in depth and allows a side-dress application that is compatible with row crops.